U.S. patent number 10,006,793 [Application Number 14/900,836] was granted by the patent office on 2018-06-26 for sensor device for detecting at least one property of a fluid medium flowing in a channel.
This patent grant is currently assigned to ROBERT BOSCH GMBH. The grantee listed for this patent is Robert Bosch GmbH. Invention is credited to Manuel Blas Sancho De Castro, Michael Eppler, Uwe Konzelmann, Edda Sommer, Holger Unger, Ulrich Wagner.
United States Patent |
10,006,793 |
Unger , et al. |
June 26, 2018 |
Sensor device for detecting at least one property of a fluid medium
flowing in a channel
Abstract
A sensor device for detecting a property of a fluid medium
flowing in a channel includes: (a) a channel piece through which a
fluid medium is able to flow, the channel piece having (i) an
inlet; (ii) an outlet; (iii) a channel piece wall including an
inner wall, an outer side connecting the inlet and the outlet, and
an insertion opening; and (iv) areas having electrical
conductivity; (b) at least one sensor having a sensor housing and a
sensor element situated in the sensor housing, the sensor housing
being insertable through the insertion opening in the channel piece
wall into the channel piece. The entire channel piece wall of the
channel piece is completely made of electrically conductive
plastic, the channel piece wall being at fixed electrical
potentials.
Inventors: |
Unger; Holger (Remseck,
DE), Sommer; Edda (Stuttgart, DE), De
Castro; Manuel Blas Sancho (Waiblingen, DE), Wagner;
Ulrich (Munich, DE), Konzelmann; Uwe (Asperg,
DE), Eppler; Michael (Ostfildern, DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
Robert Bosch GmbH |
Stuttgart |
N/A |
DE |
|
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Assignee: |
ROBERT BOSCH GMBH (Stuttgart,
DE)
|
Family
ID: |
50736076 |
Appl.
No.: |
14/900,836 |
Filed: |
May 13, 2014 |
PCT
Filed: |
May 13, 2014 |
PCT No.: |
PCT/EP2014/059767 |
371(c)(1),(2),(4) Date: |
December 22, 2015 |
PCT
Pub. No.: |
WO2014/206629 |
PCT
Pub. Date: |
December 31, 2014 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20160153819 A1 |
Jun 2, 2016 |
|
Foreign Application Priority Data
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|
|
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Jun 26, 2013 [DE] |
|
|
10 2013 212 162 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02M
35/10386 (20130101); G01F 15/14 (20130101); G01F
1/684 (20130101); G01F 5/00 (20130101); G01F
15/185 (20130101); F02D 41/187 (20130101) |
Current International
Class: |
G01F
15/14 (20060101); G01F 1/684 (20060101); F02M
35/10 (20060101); F02D 41/18 (20060101); G01F
5/00 (20060101); G01F 15/18 (20060101) |
Field of
Search: |
;73/273,272,861 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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199 46 900 |
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Dec 2000 |
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DE |
|
10 2005 057 574 |
|
Jun 2007 |
|
DE |
|
10 2005 057 575 |
|
Jun 2007 |
|
DE |
|
10 2010 020 264 |
|
Dec 2011 |
|
DE |
|
20 2011 050287 |
|
Sep 2012 |
|
DE |
|
1 855 090 |
|
Nov 2007 |
|
EP |
|
2 339 311 |
|
Jun 2011 |
|
EP |
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2 735 782 |
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May 2014 |
|
EP |
|
Other References
International Search Report for PCT/EP2014/059767, dated Jul. 23,
2014. cited by applicant.
|
Primary Examiner: Shah; Manish S
Assistant Examiner: Plumb; Nigel
Attorney, Agent or Firm: Norton Rose Fulbright US LLP
Messina; Gerard
Claims
What is claimed is:
1. A sensor device for detecting at least one property of a fluid
medium flowing in a channel, comprising: a channel piece through
which a fluid medium flows, the channel piece having an inlet and
an outlet and a channel piece wall which includes an inner wall and
an outer side connecting the inlet and the outlet, the channel
piece having an insertion opening situated in the channel piece
wall, and the channel piece including areas having electrical
conductivity; and at least one sensor having a sensor housing and a
sensor element situated in the sensor housing, the sensor housing
being configured to be selectively inserted through the insertion
opening situated in the channel piece wall into the channel piece,
and the sensor element being configured to be exposed to the
flowing fluid medium and detect at least one property of the
flowing fluid medium; wherein the entire channel piece wall of the
channel piece is completely made of electrically conductive
plastic, at least one electrically conductive contacting element
for electrical contacting of the channel piece wall being situated
one of on the outer side of the channel piece or in the cladding of
the channel piece wall, the at least one contacting element being
connected to a fixed electrical potential outside of the channel
piece so that the channel piece wall is at the fixed electrical
potential, wherein the channel piece wall or the cladding of the
channel piece wall at the fixed electrical potential causes
electrically charged particles, dirt particles or oil droplets
flowing in the channel piece not to become electrically charged, so
that an interior of the channel piece wall or the cladding of the
channel piece wall is electrically shielded, and a polarization or
charging of the particles by electrical fields in the channel piece
wall or the cladding of the channel piece wall which change
unpredictably over time is at least reduced or even precluded, and
wherein due to the channel piece wall or the cladding of the
channel piece wall which is at the fixed electrical potential, the
electrically charged particles, the dirt particles or the oil
droplets are electrically reversed or discharged upon an impact
contact with the channel piece wall or the cladding of the channel
piece wall, so as to at least reduce a likelihood of an
electrostatic force-induced deposition of these particles on the
sensor element.
2. The sensor device as recited in claim 1, wherein: the channel
piece is situated in a channel through which the fluid medium
flows, the channel including a channel interior and a channel wall,
at least portions of the fluid medium which flow through the
channel flowing through the channel piece; and the sensor housing
is inserted through the channel and the insertion opening into the
channel piece so that the sensor element is exposed to the fluid
medium flowing in the channel piece.
3. The sensor device as recited in claim 2, wherein the channel
wall of the channel is made at least partially of electrically
conductive plastic.
4. The sensor device as recited in claim 2, wherein the sensor
housing is made at least partially of electrically conductive
plastic in an area in which the sensor element is exposed to the
fluid medium.
5. The sensor device as recited in claim 1, wherein the
electrically conductive plastic has a specific electrical contact
resistance of less than 10.sup.6 .OMEGA.cm (ohm centimeters).
6. The sensor device as recited in claim 2, wherein the at least
one contacting element is configured as a screw configured to be
screwed into at least one of the channel piece wall and the channel
wall for electrical contacting of at least one of the channel piece
wall and the channel wall.
7. The sensor device as recited in claim 1, wherein the at least
one contacting element is situated in a cladding of the channel
piece wall which delimits the insertion opening.
8. The sensor device as recited in claim 7, wherein the at least
one contacting element is electrically contacted by at least one
potential plug contact situated on the sensor housing when the
sensor housing is inserted into the channel piece.
9. The sensor device as recited in claim 1, wherein a channel grate
formed of intersecting struts is situated at an inlet and/or an
outlet of the channel piece, the channel grate keeping coarse dirt
out of the interior of channel piece and influencing the flow of
fluid medium in the interior of the channel piece.
10. The sensor device as recited in claim 9, wherein the channel
grate at the inlet and/or at the outlet is electrically connected
to the channel piece wall and is at the same electrical potential
as the channel piece wall.
11. The sensor device as recited in claim 2, wherein a channel
grate formed of intersecting struts is situated at an inlet and/or
an outlet of the channel piece, the channel grate keeping coarse
dirt out of the interior of channel piece and influencing the flow
of fluid medium in the interior of the channel piece, and wherein
the channel grate is configured as an electrically conductive
channel grate by using metallic struts or electrically conductive
plastic struts.
12. The sensor device as recited in claim 11, wherein the channel
grate at the inlet and/or at the outlet is electrically connected
to the channel piece wall and is at the same electrical potential
as the channel piece wall.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sensor device for detecting at
least one property of a fluid medium flowing in a channel.
2. Description of the Related Art
In many processes, for example in the field of process engineering,
chemistry, mechanical engineering or in the field of internal
combustion engines, the process must be supplied during certain
process steps with a very particular mass of at least one fluid
medium having well-defined properties, such as a temperature or a
pressure. In particular, combustion processes which are to take
place under controlled conditions are dependent on the precise
determination of the gas mass and the properties of the fluid used.
Different types of sensors are used to determine the flow rate of
the fluid medium, its pressure and/or its temperature and are
exposed to this fluid medium.
Over the service life of such a sensor device, it is possible for
particles present in the flowing fluid to deposit on the sensor
element of the sensor device determining the properties of the
fluid medium and thus distort the measuring signal over time. In
particular, particles which have become electrically charged or
electrically polarized during their flow path are known to deposit
on the sensor element and then remain permanently adhered thereto
due to surface adhesion forces.
An air mass flow meter having a gradient field oil separation is
known from published German patent application document DE 10 2005
057 574 A1. This air mass flow meter includes a gradient field
generating device in the sensor housing in the area of the sensor
element for air mass determination, the gradient field generating
device being designed to generate an electrical field which has a
field gradient and at least partially permeates the air mass flow.
Oil droplets present in the air mass flow are electrically
polarized. Due to the gradient field, a net force acts on the oil
droplets, which may be used to drive the oil droplets away from the
sensor surface and thereby prevent a contamination of the sensor
surface.
An air mass flow meter having an electrical oil separation is known
from published German patent application document DE 10 2005 057
575 A1. This air mass flow meter includes a field generating device
in the sensor housing in the area of the sensor element for air
mass determination, the field generating device being designed to
generate a preferably at least partially homogeneous electrical
field which permeates the air mass flow. In this embodiment of the
hot film air mass flow meter, a contamination of the sensor surface
by oil droplets may be prevented by electrical effects, in
particular a deflection and/or precipitation of coagulated oil
droplets.
The approaches described in this way for reducing particle deposits
on the sensor element require a more complex design than
conventional air-flow sensors and additionally necessitate the
application of a high voltage, which is in the range of several 100
V to several 1000 V, to achieve the desired effects. To make such
voltages available, either an additional high voltage terminal must
be provided at the air-flow sensor or an additional component for
voltage conversion is needed. Moreover, these approaches focus only
on a removal of electrically charged oil droplets and do not
prevent the creation of electrically charged particles.
An air mass flow meter including a housing made of a plastic acting
in an electrically insulating manner is known from published German
patent application document DE 10 2010 020 264 A1. A flow channel
is formed in the housing of the air mass flow meter. In addition, a
sensor element, which detects the air mass flowing in the flow
channel, is situated in the housing. Furthermore, strip conductors
are situated in the housing, which connect the sensor element to
connector pins. To discharge electrostatically charged particles in
the air mass flow and protect the sensor element in this way from
the deposition of these particles, at least a portion of the flow
channel situated in the housing has electrically dissipative
properties in that this portion of the flow channel is produced,
for example, from a plastic including conductive polymers and/or a
plastic including conductive fibers and/or from plastic including
conductive carbon black.
This approach also does not prevent the creation of electrically
charged particles. With this approach, rather, already created
electrically charged particles are discharged immediately in front
of the sensor element as a result of an impact on the wall of the
flow channel situated in the sensor housing. The production of such
a device, in which portions of the sensor housing are made of
electrically insulating plastic and other portions of the sensor
housing are made of electrically conductive plastic, is complex and
expensive from a manufacturing perspective.
BRIEF SUMMARY OF THE INVENTION
Compared to the related art, the sensor device according to the
present invention for detecting at least one property of a fluid
medium flowing in a channel has the advantage that the entire
channel piece wall of the channel piece is completely made of
electrically conductive plastic, whereby the manufacture of the
channel piece may take place particularly easily and
cost-effectively in a single production step, for example an
injection molding process. As a result of at least one electrically
conductive contacting element for electrical contacting of the
channel piece wall being situated on the outer side of the channel
piece or in the wall of the channel piece, the at least one
contacting element being connectable to a fixed electrical
potential (POT) outside of the channel piece, in particular the
ground potential (GND), in such a way that the channel piece wall,
in particular the entire channel piece wall, is at the fixed
electrical potential (POT, GND), it is advantageously achieved that
a reliable electrical contact is establishable with the channel
piece in a particularly simple manner.
Due to the channel piece wall, which is at the fixed electrical
potential (POT), in particular at the ground potential (GND), a
deposition of particles, dirt particles, oil droplets or the like,
which are present in the flowing fluid medium, on the sensor
element is particularly advantageously prevented or at least
drastically reduced. In the process, two effects come to bear.
As the first effect, the channel piece wall at the fixed electrical
potential (POT, GND) advantageously causes the particles flowing in
the channel piece not to become electrically charged in the first
place, since they move in a kind of Faraday cage after their entry
into the channel piece. The interior of the channel piece is
thereby electrically shielded, and a polarization or charging of
the particles by electrical fields in the channel piece which
change unpredictably over time is thus effectively suppressed to a
strong degree or even precluded. Such electrical fields in the
channel piece which change unpredictably over time may be created,
for example, by the internal friction of the air flow on an inner
wall of the channel piece or by the friction of components
connected to the channel piece situated upstream or downstream from
the channel piece or by the irradiation of electromagnetic fields.
In particular, electrically non-conductive plastics or materials
which are not at a shared electrical potential, for example due to
the separation of electrically conducting from electrically
insulating sections, may in this way have differing charges which
vary over time in different sections of such a channel piece. Such
sections consequently also have different electrical fields acting
on the interior of the channel piece, which in turn may result in a
polarization or even electrical charging of particles.
As the second effect, due to the channel piece wall which is at the
fixed electrical potential (POT), in particular at the ground
potential (GND), it is advantageously effectuated that electrically
charged particles, dirt particles or oil droplets are electrically
reversed or discharged upon an impact contact with the channel
piece wall, and in this way the likelihood of an electrostatic
force-induced deposition of these particles on the sensor element
may be considerably reduced. This effect acts both on particles
present in the flowing fluid medium which are already electrically
charged and/or electrically polarized upon entry into the interior
of the channel piece, and on particles which are not electrically
charged and/or electrically polarized until entry into the channel
piece, for example with the aid of electrical fields induced by the
internal friction of the air flow in the interior of the channel
piece, or by electromagnetic fields irradiating from outside of the
channel piece, for example from the vehicle electronics.
The particles may essentially be solids which are made of an
electrically insulating material, for example. These solids may
then be electrically polarized, i.e., have a positive excess charge
at one end and a negative excess charge at the other end, for
example. In sum, these particles are then potentially even
electrically neutral or essentially neutral. Due to their
electrically insulating material, however, the time for a charge
equalization from one end of the particle to the other end may, in
some circumstances, take longer than the particle is situated in
the vicinity of the sensor element. As a result, it is quite
possible for a particle thus polarized to be deflected by an
electrostatic field and thus, e.g., to be drawn toward the sensor
element. Moreover, it is possible that, upon contact with a wall at
which a potential is present, possibly only the charge of the one
portion of the particle which comes in contact with the wall is
reversed, so that subsequently the sum of the electrical charges on
the particle is changed.
It is therefore particularly advantageous when the formation of an
electrical polarization, or even of an electrical charging of the
particle, is preferably suppressed utilizing the first effect.
One refinement of the present invention provides that the channel
piece is situated in a channel through which the fluid medium
flows, the channel including a channel interior and a channel wall,
at least portions of the fluid medium flowing through the channel
flowing through the channel piece, the sensor housing being
inserted through the channel and the insertion opening into the
channel piece in such a way that the sensor element is exposed to
the fluid medium flowing in the channel piece. In this refinement,
the channel may be produced from a non-conducting plastic, a
ceramic or a metal, for example. The refinement of the present
invention allows an inexpensive production of the two, for example
initially separately manufactured, elements of the channel and of
the channel piece, which considerably reduces the manufacturing
costs since a two-component injection molding process may be
dispensed with, for example.
In one further refinement of the present invention, it is provided
that the channel wall of the channel is made at least partially of
electrically conductive plastic. This advantageously causes
particles, dirt particles and/or oil droplets, which are already
present in the flowing fluid medium, to be present already prior to
entry into the channel piece in the manner of a Faraday cage, and
in this way prevents an electrical polarization or an electrical
charging, or upon impact contact between electrically charged or
polarized particles with the channel wall of the channel, the
charge of the particles is electrically reversed, or the particles
are electrically neutralized, before they flow into the channel
piece.
As a result of the sensor housing being made at least partially of
electrically conductive plastic, in particular in the area in which
the sensor element exposable to the fluid medium is situated, it is
advantageously achieved that, from a time and space perspective, an
electrical charging of particles, or an electrical polarization of
particles, is also counteracted immediately prior to such particles
flowing past the sensor element, and thus the risk of an
electrostatically induced deposition of such particles on the
sensor element is drastically reduced.
As a result of the electrically conductive plastic having a surface
resistance of less than 10.sup.12.OMEGA. (ohm), it is
advantageously achieved that the channel piece wall made of this
electrically conductive plastic is reliably at one and the same
fixed potential (POT, GND) on its inner side and on its outer wall.
In this way, the effect of an electrical shielding in the manner of
a Faraday cage in the interior of the channel piece is
advantageously particularly reliably achieved.
In one refinement of the present invention, the at least one
contacting element is designed as a screw, the screw being screwed
into the channel piece wall and/or into the channel for electrical
contacting of the channel piece wall and/or of the channel. In this
way, it is advantageously achieved that the at least one contacting
element is manufacturable particularly cost-effectively, and the
screwing in effectuates a particularly reliable and durable
mechanical and electrical contacting of the at least one contacting
element with the channel piece wall or with the channel. In this
way a permanent particularly low electrical contact resistance is
particularly advantageously achieved between the at least one
contacting element and the channel piece wall and/or the channel
wall.
As a result of the at least one contacting element being situated
in the cladding of the channel piece wall which delimits the
insertion opening, and the at least one contacting element being
electrically contacted by at least one potential plug contact
situated on the sensor housing when the sensor housing is inserted
into the channel piece, it is advantageously achieved that the at
least one contacting element is securely and reliably electrically
and mechanically contacted in a particularly simple manner, and
that in this way the channel piece wall is connected to the fixed
electrical potential (POT, GND) particularly reliably. The further
advantage of such a specific embodiment is that, as a result of the
thus situated at least one contacting element, this at least one
contacting element does not project outwardly or into the interior
of the channel piece, whereby damage of the contacting element
and/or of the channel piece wall, for example, during the
manufacturing process or during transport, is prevented.
Specific embodiments of the present invention are shown in the
drawings and are described in greater detail in the following
description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a shows a perspective view of a first specific embodiment of
a sensor device according to the present invention.
FIG. 1b shows a cross section through one specific embodiment of
the sensor of FIG. 1a.
FIG. 2 shows a perspective cross section through a second specific
embodiment of the sensor device according to the present
invention.
FIG. 3 shows a cross section through a third specific embodiment of
the sensor device according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1a shows a first specific embodiment of a sensor device 100
according to the present invention for detecting at least one
property of a fluid medium flowing in a channel. Sensor device 100
includes a channel piece 110 in the form of a flow tube through
which the fluid medium is able to flow. At its two open ends
situated in the axial extension direction, channel piece 110
includes an inlet 111 and an outlet 112 for the fluid medium
flowing in the axial direction along the arrow shown in the figure.
Tubular channel piece 110 furthermore includes a channel piece wall
116, which has an inner wall 117 and an outer side 118 connecting
inlet 111 and outlet 112. Channel piece 110, together with its
entire channel piece wall 116, is made completely of electrically
conductive plastic 200.
Fluid medium within the meaning of the present application shall be
understood to mean gaseous and/or liquid media or chemicals of all
types, for example, air, exhaust gases, water, urea-water solution,
fuels, cooling media, oils, water vapor, nitrogen, oxygen,
hydrogen, methane, propane, butane, and the like, whose mass flow
may be determined. Generally, sensor device 100 according to the
present invention may be used to determine the mass flow of any
fluid medium. Sensor device 100 according to the present invention
may also be used to determine another property of the fluid medium,
for example the absolute pressure of the fluid medium or a
differential pressure as a difference of absolute pressures, of
which at least one is attributable to the fluid medium.
The material of electrically conductive plastic 200 is composed of
a plastic matrix which is electrically insulating in the pure state
and to which electrically conductive fillers may be admixed for
creating an electrically conductive plastic. Fillers may be, for
example, metal powders, carbon black, carbon fibers, metal fibers,
solder alloys, so-called carbon nanotubes or other nanoparticles.
The fill level must exceed a certain minimum amount in order to
form a sufficient number of electrically conductive paths within
the material composite made up of the plastic matrix and the
fillers. Starting at this so-called percolation limit, the
electrical resistance is no longer infinitely large, and the
electrical conductivity increases.
Such a composite material preferably reaches a specific electrical
contact resistance of less than 10.sup.6 .OMEGA.cm (1,000,000 ohm
centimeters), preferably of less than 1000 .OMEGA.cm or less than
500 .OMEGA.cm, most particularly preferably of less than 100
.OMEGA.cm. For the shielding effect of electrical or
electromagnetic fields in the interior of channel piece 110 in the
manner of a Faraday cage, the specific electrical contact
resistance of the material of channel piece 110 and of channel
piece wall 116 is particularly crucial. It is also crucial that the
entire channel piece wall 116 is made of the electrically
conductive material. To achieve this specific electrical contact
resistance, the composite material contains between 0.1 vol. % and
70 vol. % electrically conductive fillers, for example.
In one preferred specific embodiment, such a composite material
reaches a specific electrical surface resistance of less than
10.sup.12.OMEGA. (10 to the power of 12 ohm), the specific surface
resistance is preferably in a range from 10.sup.2 ohm to 10.sup.11
ohm, most particularly preferably the specific surface resistance
is in a range from 100 ohm to 10,000 ohm (10.sup.2 ohm to 10.sup.4
ohm). In a further preferred range from 10.sup.6 ohm to 10.sup.11
ohm of the specific surface resistance, the specific surface
resistance has so-called electrically dissipative properties.
The definition of the specific electrical contact resistance and of
the specific electrical surface resistance and measuring methods
for these two values are described in detail in the standard DIN
IEC 60093 in the issue from December 1993 (Classification VDE 0303
Part 30).
In the shown specific embodiment of the present invention, a
channel grate 114 formed of intersecting struts is situated at
inlet 111 of channel piece 110, the channel grate keeping coarse
dirt out of the interior of channel piece 110 and influencing the
flow of fluid medium in the interior of channel piece 100. Channel
grate 114 is preferably designed as an electrically conductive
channel grate 115, for example by using metallic struts or struts
produced from an electrically conductive plastic 200. A design as a
metallic, electrically conductive channel grate 115 is also
possible. Such a channel grate 114, preferably as an electrically
conductive channel grate 115, may also be situated at outlet 112.
Channel grate 114 at inlet 111 or at outlet 112 is preferably also
electrically connected to channel piece wall 116 and is at the same
electrical potential as channel piece wall 116.
Radially on its outer side 118, channel piece 110 furthermore has
an insertion opening 113, which is suitable for inserting or
introducing a sensor 120, which is also an integral part of the
sensor device, into channel piece 110. This sensor 120 may be an
air-flow sensor 130, for example, or a pressure sensor 132, or any
arbitrary other sensor, which is suitable for detecting at least
one property of a flowing fluid medium. Sensor 120 is preferably
inserted into channel piece 110 in the radial direction.
Channel piece 110 furthermore includes at least one electrically
conductive contacting element 180 having a first end 182 and a
second end 184 facing away from first end 182. Contacting element
180 is mechanically fixed to channel piece wall 116, for example
with its first end 182, and electrically connected to channel piece
wall 116. The contact surfaces and the material of the at least one
contacting element 180 are preferably designed in such a way that
the electrical contact resistance between the at least one
contacting element 180 and channel piece wall 116 is permanently
preferably low. The at least one contacting element 180 is designed
as a screw 186, for example, for fixation to channel piece wall
116, the at least one contacting element 180, 186 at its first end
182 having a screw thread with which contacting element 180, 186 is
screwed into channel piece wall 116. Via an electrical line 210,
second end 184 of the at least one contacting element 180 is
electrically connected to a fixed electrical potential (POT)
provided outside of channel piece 110, preferably to ground
potential (GND). As a result of channel piece 110 made of
electrically conductive plastic 200, it is thus ensured that the
entire channel piece wall 116 and electrically conductive channel
grate 115 at inlet 111 and outlet 112 are electrically at fixed
electrical potential (POT), in particular ground potential (GND).
This design creates a kind of Faraday cage in the interior of
channel piece 110, through which the flowing fluid medium flows
together with particles possibly contained therein.
In the radial direction, a sensor 120 is introduced into channel
piece 110 through insertion opening 113 in the shown specific
embodiment of the present invention. Sensor 120 is an air-flow
sensor 130 or a pressure sensor 132, for example. Sensor 120
includes a sensor housing 126 in which a carrier substrate 127 is
situated. Carrier substrate 127 is designed as a circuit board
(PCB) including strip conductors or as a ceramic carrier substrate.
On its first sensor end 147 projecting into the interior of channel
piece 110, sensor housing 126 of sensor 120 furthermore includes a
flow channel 128 which is exposed to the flowing fluid medium
through an opening facing the flow direction in channel piece 110.
Flow channel 128 is preferably introduced in a curve-shaped manner
into sensor housing 126 and the fluid medium flows through the same
along the arrows indicated in flow channel 128. Sensor 120
furthermore includes a sensor element 122, which is situated on
carrier substrate 127 and projects into flow channel 128. Sensor
element 122 is used to detect the at least one property of the
flowing fluid medium. Sensor element 122 is directly or indirectly
electrically connected to plug contacts 142 which are situated on a
connector element 140 of sensor housing 126. Connector element 140
is situated at a second sensor end 148 of sensor housing 126 which
projects outwardly with respect to channel piece 110 and faces away
from first sensor end 147 and may be electrically contacted with
the aid of a mating connector 500.
FIG. 1b shows sensor 120 shown in FIG. 1a in greater detail.
Identical reference numerals denote the same features. Adjoining
second sensor end 148 designed as connector element 140, sensor
housing 126 of sensor 120 includes a recess 144 in which a sealing
element 146, for example a commercially available O-ring, is
mounted. With the aid of recess 144 and sealing element 146, sensor
housing 126 may be fixed securely and preferably in a fluid-tight
manner in channel piece 110, for example by latching in insertion
opening 113. Sensor element 122 situated on carrier substrate 127
is electrically connected to carrier substrate 127 with the aid of
electrical connecting elements. Electronic components 124, for
example in the form of application-specific integrated circuits
(ASICs), and passive electrical components 125, for example in the
form of resistors, capacitors or coils, are situated on carrier
substrate 127. Carrier substrate 127 itself is electrically
connected to plug contacts 142 of connector element 140 with the
aid of electrical connecting elements, such as bond wires.
The fluid medium flowing in FIG. 1b from left to right in the
direction of the arrow flows in a serpentine manner through flow
channel 128 situated at first sensor end 147. An inlet opening of
flow channel 128 is situated on the left side of sensor housing 126
which faces the flow, while an outlet opening of flow channel 128
is situated on the side of the sensor housing which is directed
downward in FIG. 1b. The inlet opening and the outlet opening of
flow channel 128 and the shape of flow channel 128 may be adapted
to the desired purpose of the sensor, other specific embodiments of
the shape of flow channel 128 and of the position of its inlet
opening and its outlet opening than shown in FIG. 1b also being
possible.
Sensor housing 126 is preferably made of a non-conducting plastic,
such as polybutylene terephthalate (PBT). To reduce the risk of an
electrostatically induced deposition of particles on sensor element
122, however, in one preferred specific embodiment first sensor end
147, or also only portions of flow channel 128, may be made of an
electrically conductive plastic 200 so that the effect of the
Faraday cage also covers immediate surroundings of sensor element
122. In such an embodiment, sensor element 122 situated in sensor
120 is particularly reliably protected against the increased
deposition of particles present in the flowing medium due to
electrostatic charging.
FIG. 2 shows a further specific embodiment of the present
invention. In this specific embodiment of sensor device 100
according to the present invention, channel piece 110 is situated
in an interior 152 of a channel 150. Channel 150 includes a channel
wall 160 having a channel inner cladding 167 and a channel outer
side 168. The flowing fluid medium flows through tubular channel
150 in an axial direction along the arrows shown in FIG. 2.
Portions of the flowing fluid medium reach the interior of channel
piece 110 through inlet 111 of channel piece 110. There, the at
least one property of the flowing fluid medium, for example a
pressure, a temperature or an air mass, is determined with the aid
of sensor 120, together with its sensor element 122, introduced
through channel wall 160 and insertion opening 113 of channel piece
110.
Channel wall 160 may be made of an electrically insulating material
or else of an electrically conductive material, for example an
electrically conductive plastic 200. The connection of channel
piece 110 and its channel piece wall 116 to fixed electrical
potential (POT), in particular ground potential (GND), is
established via the at least one electrical contacting element 180
on channel piece wall 116, electrical line 210, a further
electrical contacting element 190 situated in channel wall 160 of
channel 150, and a further electrical line 211. Further electrical
contacting element 190 is preferably designed as an electrical
feedthrough through channel wall 160 and suitable for placing a
channel wall 160 made of electrically conductive plastic 200 also
at fixed electrical potential (POT), in particular ground potential
(GND). Further electrical contacting element 190 is moreover
suitable for electrically contacting and mechanically fixing the
further electrical line 211 on the side of the contacting element
which faces outer side 168 of channel 150. Moreover, electrical
line 210 may be electrically contacted and mechanically fixed on
the side of further contacting element 190 which faces interior 152
of channel 150.
In this specific embodiment of the present invention, sensor 120
projects with its first sensor end 147 in the radial direction into
channel piece 110, while its connector element 140 formed at second
sensor end 148 projects with plug contacts 142 out of channel outer
side 168 and is electrically contactable with the aid of a mating
connector 500.
Channel piece 110 and/or channel 150 may be injection molded or
extruded, for example. Multi-component injection molding processes
and/or plastic welding processes lend themselves to creating
electrically insulating areas, for example in channel 150. In this
way, workpieces may be manufactured which are fluid- and
pressure-tight and which, in addition to the electrically
conductive plastic, may also contain insulating plastics or other
electrical insulating materials (insulators) or electrical
components, such as electrically conductive contacting elements
180, 190.
FIG. 3 shows a third specific embodiment of sensor device 100
according to the present invention. In this specific embodiment,
the at least one electrical contacting element 180 is not situated
on outer side 118, and also not on inner wall 117, of channel piece
wall 116, but in the cladding of channel piece wall 116 which
delimits insertion opening 113. In this way, the at least one
electrical contacting element 180 no longer projects in the radial
direction outwardly from channel piece wall 116 or into the
interior of channel 150, but to a certain extent projects from the
cladding delimiting insertion opening 113 in the axial direction
into insertion opening 113. In this way, electrical contacting
element 180 is particularly easily connectable to a potential plug
contact 143 of sensor 120. For example, potential plug contact 143
is contactable with one end in connector element 140 of sensor 120
by a mating connector 500 and is conducted at the other end through
the wall of sensor housing 126 in such a way that it makes
electrical contact with the at least one electrical contacting
element 180 when sensor 120 is inserted into insertion opening 113.
Electrical contacting element 180 may also be designed as an
electrically conductive coating, which is applied to a larger area
of the cladding delimiting insertion opening 113 or even to the
entire cladding delimiting insertion opening 113. Such an
electrically conductive coating may be created, for example, with
the aid of vapor deposition or a galvanic process. Metallic
materials, preferably copper, silver or gold, are preferably
suitable materials for such a coating. Such a coating which covers
a larger area of the cladding delimiting insertion opening 113 and
acts as the at least one contacting element 180 allows a
particularly simple and secure contacting with a potential plug
contact 143 situated in sensor housing 126. In its contact area
with the at least one contacting element 180, matching potential
plug contact 143 is formed, for example by an electrically
conductive contact electrode surrounding sensor housing 126 in an
annular manner, which is not shown here. This results in a
particularly simple assembly with particularly reliable contacting,
a particularly simple production of sensor housing 126 and, due to
the large contacting surface, a particularly low electrical contact
resistance between the at least one contacting element 180 and
potential plug contact 143.
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